Synopsis:"Twilight Online" is a thriller based on two real incidents: the 2003 Tuen Mun Road traffic accident that claimed 21 lives and the 2013 Yau Oi Estate suicide, where the female victim dressed in red leapt to her death on the day of the Chinese Ghost Festival.

In 2003, a double-decker bus collided with a truck and plunged 35 meters off a bridge, crashing to the village below. The bodies of the passengers were thrown from the bus and scattered throughout Ting Kau Village. Tens years later, at the site of the horrific accident, sightings of a female ghost dressed in red are reported. POON, the host of the radio show "Twilight Online", discovers the identity of the ghost; she was a teacher, named LUI, who taught at the Good Moral College. He decides to visit the village and conduct a paranormal investigation. Four female students and a male teacher from the school volunteer to help. They believe that Lui's spirit has returned to redress unresolved grievances. During the evening, the four female students sense the presence of the ghost. The students disappear one by one. Their bodies are later discovered; each has suffered a horrible death?

Meanwhile, veteran policeman, INSPECTOR GU and his new sidekick BEE have been assigned to investigate sightings of the female suicide victim dressed in red at Yau Oi Estate, a public housing complex where a week earlier, a woman, fitting the same description, leapt to her death on the day of the Chinese Ghost Festival. According to Chinese superstition, when someone commits suicide, dressed in red, they will return to seek vengeance. As Gu probes deeper into the case, he begins to suspect that there's a connection between the ghost haunting Ting Kau Village and the sightings of the suicide victim at Yau Oi Estate. Meanwhile, Gu grows increasingly alarmed by Bee's strange behavior. Nothing is as it appears. The vengeful ghost may hold the key to unearthing long buried secrets..."